Fiber optic connectors employing elements to mechanically retain a terminating fiber are known. U.S. Pat. No. 5,381,500 to Edwards et al. discloses an elastomeric insert disposed within a fiber optic ferrule that receives a terminating fiber through an aperture in the insert. An axial displacement member has a bore coaxial with the aperture in the insert. The bore receives the terminating fiber and the axial displacement member compacts the insert in a constriction in the ferrule. In response to compaction, the aperture in the insert radially compresses the fiber, retaining it. Advantageously, the mechanical fiber retention permits straight forward field assembly by obviating the need to handle epoxy and curing ovens during field termination. In an embodiment of a fiber optic connector according to the teachings of the invention disclosed in U.S. Pat. No. 5,381,500 and subsequent to fiber retention, a presentation endface of the fiber in the fiber optic connector is cleaved and polished to complete the connector termination. The polishing process requires skilled labor and in certain cases, special equipment. It is desirable to omit performance of the polishing step in the field by preparing the presentation endface of the fiber optic connector at a factory location.
U.S. Pat. No. 4,743,084 to Manning discloses a fiber stub disposed in a fiber optic ferrule and having a pre-polished presentation endface. A terminating fiber is brought into mating contact with a splicing endface of the fiber stub to terminate the fiber optic connector. A radial crimp is applied to complete termination of the fiber optic connector and to retain the fiber in mating relation with the splicing endface of the fiber stub. Advantageously, in an embodiment of a connector according to the teachings of the U.S. Pat. No. 4,743,084, the presentation endface of the fiber stub may be polished prior to field termination to achieve the benefits of high quality endface finishing while reducing the field termination time. Disadvantageously, the radial crimp must be very carefully controlled to assure appropriate fiber retention and alignment.
U.S. Pat. No. 5,040,867 issued to de Jong et al. discloses a fiber optic connector having a pre-polished fiber stub at a presentation endface and a mechanical fiber retention system in which a tab of a frame extends through a slot in a ferrule. A slider positioned over the housing is slid axially forward and engages the tab urging the tab radially inward through the slot to center the connector. Disadvantageously, the radial force applied to the fiber as the slider is positioned over the tab is unevenly distributed and may result in misalignment and/or insufficient fiber retention. Insertion loss of the connector is partially determined by the alignment of the terminating fiber to the splicing endface. The mechanisms internal to the connector, therefore, should perform fiber to fiber alignment as well as fiber retention. It is desirable, therefore, to improve the fiber to fiber alignment and improve the repeatability of the termination process in a pre-polished fiber optic connector.
Accordingly, there is a need to provide a fiber optic connector that may be easily and reliably field terminated and to provide one that is less sensitive to installation process variations. It is an advantage if an improved fiber optic connector were also interchangeable with one or more known coupling formats in order to achieve manufacturing economies of scale.